GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Envoy - 4WD 🢒 Engine 🢒 Engine Electrical 🢒 Cuts Out, Misses

Checks

Action

DEFINITION: A jerking that follows engine speed, usually more pronounced as the engine load increases which is not normally felt above 1,500 RPM or 48 km/h (30 mph).

Preliminary Check

Refer to Symptoms - Engine Controls .

Ignition System Checks

Check for a cylinder misfire:

  1. Start the engine.
  2. Allow the engine to stabilize.

    3. Notice: Do not perform this test for more than 2 minutes in order to prevent damaging the catalytic converter.

  3. Perform the Cylinder Power Balance Test with a scan tool.
  4. If there is a RPM drop on all cylinders, equal to within 50 RPM, refer to Rough, Unstable, or Incorrect Idle and Stalling .
  5. If there is no spark, refer to Engine Cranks but Does Not Run .
  6. If there is spark, remove the spark plugs in these cylinders and check for the following conditions:
    7. • Insulation cracks
    • Wear
    • Improper gap
    • Burned electrodes
    • Heavy deposits
    • The ignition system for moisture, dust, cracks, burns, etc.
  7. Perform the Fuel Injector Balance Test. Refer to Fuel Injector Balance Test with Tech 2 .

Engine Mechanical Checks
    • Perform a cylinder compression check.
    • Check the engine for the following:
       - Improper valve timing
       - Bent pushrods
       - Worn rocker arms
       - Worn camshaft lobes
       - Broken or weak valve springs -- Refer to Upper Engine Noise, Regardless of Engine Speed in Engine Mechanical.
       - Check the intake and exhaust manifold passages for casting flash.

Fuel System Checks
    • Check the fuel pressure. Refer to Fuel System Diagnosis .
    • Check for water contamination in the fuel.
    • Perform the fuel injector coil test. Refer to Fuel Injector Solenoid Coil Test .
    • Perform the fuel injector balance test. Refer to Fuel Injector Balance Test with Tech 2 .